The Sunscreen Of The Future

IRA FLATOW: There is no perfect way to protect your skin from sun damage, and whether you have to lather up constantly or never get a sunburn depends on the pigment, the melanin, that makes up your skin. Now, melanin produced by your body isn’t something you can change at will. But a group of researchers has discovered a way to create a melanin-like substance in the lab that can be tuned to different shades, darker or lighter, which corresponds with UV protection.

So could we soon see products containing melanin-like material replacing the traditional sunscreens on the market today? Here with me to discuss this new research is my guest Rein Ulijn, professor of chemistry and director of the Nanoscience Initiative at the Advanced Science Research Center at City University here in New York. Welcome to Science Friday.

REIN ULIJN: Thank you for having me.

IRA FLATOW: So what’s the connection between melanin and its UV properties on your body?

REIN ULIJN: So melanin is an incredibly interesting material that serves many functions across all living species. It is– it provides UV protection, it provides free radical scavenging, and it can also have other properties like mechanical properties. And so it’s a protective layer found in many species.

The way it’s produced in the biological context is it’s essentially made in small organelles known as melanosomes. And there’s a polymerization reaction that takes place inside these melanosomes, and that makes the melanin-like material. And as you’re exposed to UV more, the body responds to that and produces more of that material.

IRA FLATOW: So is your research saying that, basically, you have made synthetic melanin?

REIN ULIJN: It’s not strictly synthetic melanin, I would say, because it has some chemical signatures that are slightly different. So the purist would say it’s not synthetic melanin. However, it’s potentially even more exciting because it is highly tunable, and you can control the properties of this synthetic melanin mimic.

IRA FLATOW: So it changes color when you put it in UV? It’s in a Petri dish, and you shine light on it, and it turns darker?

REIN ULIJN: Not dynamically like that. Let me try to explain how it works. So the way biology does this is, as I said, by a polymerization reaction that starts with tyrosine, a common amino acid found everywhere in the body. So tyrosine is polymerized. It’s first oxidized to a highly reactive oxidizing species. And these polymerize, so these form long, complex chains of molecules. And you end up with a polymer, a network-type polymer that then has the unique melanin properties.

The difficulty is, though, that– or the cool thing about biology is that this is all very tightly regulated. So it is a polymerization that’s guided, and it’s guided by assembly of these precursors. So they’re not just freely available to react, you know, where they can. They are presented appropriately so that a tunable melanin and a reproducible melanin is formed.

And that’s been very difficult to reproduce in the lab. So if you take tyrosine and you oxidize it in the lab, you can make black insoluble polymers. But they are not very useful because they don’t have tunable and precise properties.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI, Public Radio International. In case you joined us, we’re talking with Rein Ulijn of CUNY here. So you got– but now you’re able to tune it to different colors. And what practical use now can we make? Can you make a cream out of this or what?

REIN ULIJN: Yeah, so let me first quickly explain how we tune it because that’s–

IRA FLATOW: We only have a few minutes left in the show.

REIN ULIJN: Right. So the tunability relates to how we pre-organize the tyrosine molecules. And that gives us the different colors. So yes, you now have a material that has properties that are dependent on the ingredients that you put in in the first place.

So you could process this in water to, ultimately, have an ingredient that you could add to cosmetic creams. And we– I mean, I’m not a cosmetics expert, but we’ve talked to a couple of cosmetics companies. And they believe that these things have real applications as ingredients for cosmetic products.

IRA FLATOW: And how much of the ultraviolet could you actually block out?

REIN ULIJN: So what we have so far is we’ve demonstrated that we can cover the UVA and UVB range depending on, again, the ingredients. So that’s the tunability. We can access UVA more or UVB more. So, yes, we can have a level of SPF. How it compares with existing materials is hard to tell at the moment.

IRA FLATOW: So I’m envisioning sort of a switch or something– that I can change the color of my melanin that I’m putting on– the synthetic stuff that you’re making.

REIN ULIJN: Yeah. It’s not an in-situ switch, it is a– but it is a predetermined switch. So you would have to, in advance, decide what kind of pigmentation you’re looking for. And, in that sense, it is tunable.

IRA FLATOW: So could you go into a tanning center, like we have now? Instead of getting exposed to UVA or whatever, you could be sprayed with– all over your body with what you have? Or are you thinking it’s more topical [INAUDIBLE].

REIN ULIJN: It’s more topical, actually. It’s nothing to do with the tanning station. It would be really like a– you know, think about a cosmetic product that has SPF built in. Those are very, very common. So this could be an ingredient that replaces the existing SPF.

IRA FLATOW: Any FDA approval yet?

REIN ULIJN: No. We are– it’s early days. We’ve been doing this for the past year, but we are hopeful because all the ingredients that we use to make these materials are themselves derived from amino acids. And they have a good status at the FDA. They have so-called grass status.

IRA FLATOW: Yeah, I know what that is. What else? What’s the one thing that’s missing now? Where to next?

REIN ULIJN: Well, there’s a lot more that needs to be done. I mean, despite the fact that we can now control the formation of these materials much better than what was possible previously, there are still many questions about exactly how the chemical connection works and how exactly these– really the function relates to the molecular properties. So this is something that can keep us going for quite some time.

There are also more exotic applications. We’re working with a collaborator at Carnegie Mellon University, Christopher Bettinger, who’s looking at battery-like applications of these materials. So there’s no shortage of exciting things that can be done, now that we can tune the formation of these materials.

IRA FLATOW: Battery charging? Battery with solar, maybe?

REIN ULIJN: Not solar-charged. It would be an ion storage capacity, so releasing ions on demand and use that as electric storage.

IRA FLATOW: Wow. So you could start out with melanin for the skin and wind up with a breakthrough in battery storage technology.

REIN ULIJN: I don’t know–

IRA FLATOW: What path you might take on it.

REIN ULIJN: Yes. Well, that will be probably a decade down the line. But certainly as scientists, it keeps us excited and keeps us going.

IRA FLATOW: We like it when you get excited. Thank you, Rein Ulijn, professor of chemistry, director of the Nanoscience Initiative at CUNY’s Advanced Science Research Center. Thanks, Rein.

REIN ULIJN: Thank you.

IRA FLATOW: [INAUDIBLE] be with us today.

Copyright © 2017 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of ScienceFriday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/